Immune deviation induced by ocular antigen presenting cells involves a protective peripheral immune response that prevents inflammation. Such anti-inflammatory immune response plays a significant role in avoiding potentially blinding effects of ocular inflammation. The unique ability of ocular APCs to induce such a protective response is attributed to their exposure to TGF-2 in their local microenvironment. Studies described in this proposal seek to elucidate molecular mechanisms utilized by such TGF-2-exposed APCs in inducing a regulatory immune response. The first specific aim seeks to determine the significance of thrombospondin-1 (TSP-1) in the induction of a peripheral population of regulatory T cells. Since we demonstrated earlier that TSP-1 is essential for ocular immune privilege, experiments in this aim will allow us to determine the effect of TSP-1 on peripheral immune effectors. The second aim seeks to investigate the specific contribution of the interactions of TSP-1 with its receptors on the effectors, which subsequently suppress inflammatory immune response. Considering the multidomain structure of a large molecule like TSP-1 with multiple cell type specific biological effects, these investigations will clarify mechanisms by which TSP-1 contributes to immune deviation. The final aim addresses the relevance of TSP-1 dependent mechanisms in regulation of autoimmune ocular inflammatory conditions as seen in experimental autoimmune uveitis (EAU) and Sjogren's syndrome associated ocular surface disease dry eye. Since TSP-1 is known to be important in maintaining immune privilege these studies will allow us to evaluate if application of any of the TSP-1 dependent mechanisms can help resolve chronic ocular inflammatory diseases. Together these studies can build further on the existing knowledge of ocular immune responses and provide insights into novel therapeutic strategies. PUBLIC HEALTH RELEVANCE: Immune privilege of the eye is an evolutionary phenomenon that protects the eye from potential vision-compromising inflammatory immune response. Understanding immunologic mechanisms underlying this phenomenon can help improve current therapeutic approaches used to treat ocular inflammation. The long-term goal of these investigations is to develop novel anti-inflammatory therapeutic strategies to counter inflammatory conditions such as autoimmune diseases and transplant rejections.